let Dp be non empty Subset of (TOP-REAL 2); :: thesis: for f being Function of ((TOP-REAL 2) | Dp),I(01)
for C being non empty Subset of (TOP-REAL 2) st f is being_homeomorphism & C c= Dp & ex p1, p2 being Point of I[01] st
( p1 < p2 & f .: C = [.p1,p2.] ) holds
ex s1, s2 being Point of (TOP-REAL 2) st C is_an_arc_of s1,s2
let f be Function of ((TOP-REAL 2) | Dp),I(01) ; :: thesis: for C being non empty Subset of (TOP-REAL 2) st f is being_homeomorphism & C c= Dp & ex p1, p2 being Point of I[01] st
( p1 < p2 & f .: C = [.p1,p2.] ) holds
ex s1, s2 being Point of (TOP-REAL 2) st C is_an_arc_of s1,s2
let C be non empty Subset of (TOP-REAL 2); :: thesis: ( f is being_homeomorphism & C c= Dp & ex p1, p2 being Point of I[01] st
( p1 < p2 & f .: C = [.p1,p2.] ) implies ex s1, s2 being Point of (TOP-REAL 2) st C is_an_arc_of s1,s2 )
assume A1:
( f is being_homeomorphism & C c= Dp )
; :: thesis: ( for p1, p2 being Point of I[01] holds
( not p1 < p2 or not f .: C = [.p1,p2.] ) or ex s1, s2 being Point of (TOP-REAL 2) st C is_an_arc_of s1,s2 )
given p1, p2 being Point of I[01] such that A2:
( p1 < p2 & f .: C = [.p1,p2.] )
; :: thesis: ex s1, s2 being Point of (TOP-REAL 2) st C is_an_arc_of s1,s2
reconsider E = [.p1,p2.] as Subset of I(01) by A2;
set g = (f " ) | E;
f " is being_homeomorphism
by A1, TOPS_2:70;
then A3:
f " is one-to-one
by TOPS_2:def 5;
A4:
( f is continuous & f is one-to-one )
by A1, TOPS_2:def 5;
A5:
f " (f .: C) = C
A6:
rng f = [#] I(01)
by A1, TOPS_2:def 5;
then A7:
(f " ) .: E = C
by A2, A4, A5, TOPS_2:68;
A8: rng ((f " ) | E) =
(f " ) .: E
by RELAT_1:148
.=
[#] ((TOP-REAL 2) | C)
by A7, PRE_TOPC:29
;
the carrier of (I(01) | E) = E
by PRE_TOPC:29;
then
(f " ) | E is Function of the carrier of (I(01) | E),the carrier of ((TOP-REAL 2) | Dp)
by FUNCT_2:38;
then reconsider g = (f " ) | E as Function of (I(01) | E),((TOP-REAL 2) | C) by A8, FUNCT_2:8;
dom (f " ) = the carrier of I(01)
by FUNCT_2:def 1;
then dom g =
E
by RELAT_1:91
.=
the carrier of (I(01) | E)
by PRE_TOPC:29
;
then A9:
dom g = [#] (I(01) | E)
;
A10:
g is one-to-one
by A3, FUNCT_1:84;
( the carrier of ((TOP-REAL 2) | C) = C & the carrier of ((TOP-REAL 2) | Dp) = Dp )
by PRE_TOPC:29;
then A11:
(TOP-REAL 2) | C is SubSpace of (TOP-REAL 2) | Dp
by A1, TOPMETR:4;
f " is continuous
by A1, TOPS_2:def 5;
then A12:
g is continuous
by A11, Th69;
A13: g " =
g "
by A8, A10, TOPS_2:def 4
.=
((f " ) " ) | ((f " ) .: E)
by A3, RFUNCT_2:40
.=
((f " ) " ) | ((f " ) .: E)
by A4, A6, TOPS_2:def 4
.=
f | C
by A4, A7, FUNCT_1:65
;
then reconsider t = f | C as Function of ((TOP-REAL 2) | C),(I(01) | E) ;
reconsider C' = C as Subset of ((TOP-REAL 2) | Dp) by A1, PRE_TOPC:29;
((TOP-REAL 2) | Dp) | C' = (TOP-REAL 2) | C
by A1, PRE_TOPC:28;
then
t is continuous
by A4, Th69;
then
g is being_homeomorphism
by A8, A9, A10, A12, A13, TOPS_2:def 5;
then
I(01) | E,(TOP-REAL 2) | C are_homeomorphic
by T_0TOPSP:def 1;
hence
ex s1, s2 being Point of (TOP-REAL 2) st C is_an_arc_of s1,s2
by A2, Th79; :: thesis: verum